Nonlinear sheath dynamics in dual-frequency argon plasmas with two-stack dielectric structure

Capacitively coupled plasmas (CCPs) are widely used in plasma processing applications such as dry etching. Effective control of electron heating and ion behavior requires a detailed understanding of sheath dynamics, which play a critical role in plasma–surface interactions. To enable independent control over ion flux and ion energy, dual-frequency excitation has been extensively studied in recent years. Introducing a two-stacked dielectric structure allows for modulation of the equipotential lines, thereby enabling control over the ion energy and angular distributions. This structural modification results in distinctly different sheath behavior and ion trajectories compared with single-frequency systems. In this study, we employ spatiotemporal analysis to investigate how the stacked dielectric structure alters sheath dynamics. Using a GPU-accelerated 2D particle-in-cell (PIC) simulation [1], we examine key plasma characteristics—including sheath dynamics, electron flux, ion energy and angular distributions, and field reversals—in CCPs with a two-stack dielectric configuration. The findings provide valuable insights into the impact of dielectric architecture on plasma behavior, contributing to the optimization of CCP designs for advanced plasma processing applications.